The present invention relates generally to an image recording body and an image forming apparatus by use of the image recording body, and more particularly to a structure of the image recording body in order to form a latent image by means of a light (or heat)-stimulated writing method, improvement of a light-to-heat conversion efficiency during a light-stimulated writing operation, a long-life operation of a source for writing, an adjustment of a light (or heat) amount during the light-stimulated writing operation, a method for removing an ink remaining on the image recording body and a method for forming the latent image thereon.
FIG. 1 illustrates a schematic view of an essential part of an image forming apparatus of an embodiment according to the present invention. As shown in FIG. 1, the image forming apparatus comprises a heating source 1, a recording roller 2, an inking unit 3, an intermediate transfer roller 4, a recording paper 5, a pressure roller 6, an infrared heater 7, a cleaning unit 8, a liquid layer-forming roller 9 and an image recording body 10. Examples of the heating source 1 (preferably light source having a wavelength from 300 nm to 1300 nm) include a light-emitting diode array (which is hereinafter referred to as LED array), a semiconductor laser, a solid laser or the like. The image recording body 10 has surface characteristics that a receding contact angle decreases when a surface of the image recording body in a heated state is brought into contact with a liquid (hereinafter referred to as a liquid-attracting state), and the receding contact angle increases when the image recording body is heated in a state where the image recording body is not contact with the liquid (hereinafter referred to as a liquid-repelling state).
When the surface of the image recording body 10 is treated to become the liquid-attracting state, a liquid layer is formed on the surface of the image recording body 10 before the surface of the image recording body 10 is heated, or a liquid is come into contact with the surface of the image recording body 10 during a heating operation, or the liquid is come into contact with the surface of the image recording body 10 right after the surface is heated. As shown in FIG. 1, it is possible to form the liquid layer on the image recording body 10 by means of the liquid layer-forming roller 9. However, it is not necessary to use the liquid layer-forming roller 9 for formation of the liquid layer. For example, it is possible for the image recording body 10 to remove from the recording roller 2 or for the recording roller 2 to dip in the liquid, or for the liquid layer to form on the surface of the image recording body 10 by means of the cleaning unit 8.
As mentioned above, after the surface of the recording body becomes the liquid-attracting state, writing of an image can be carried out thereon. This image writing can be performed by scanning the heating source 1 with separation of the image recording body 10 from the inking unit 3, the intermediate transfer roller 4, the cleaning unit 8 or the like. As a scanning method, writing can be carried out by moving the heating source 1 in a main scanning direction by a linear motor or the like while rotating the recording roller 2, or a raster scanning can be applied for writing by means of polygon mirror or galvano mirror.
The image is then formed on the image recording body 10 and at this image forming period the recording paper 5 is fed while pressing the image recording body 10 with the intermediate transfer roller 4 and the inking unit 3. As the inking unit 3, a plurality of inking rollers can be used in order to control a thickness of an ink layer by means of a blade or the like 3b. An ink can be supplied from an upper portion of the blade 3b by dropping an ink from an ink supply container 3a. 
After printing a desired press run, it is possible to reuse the image recording body 10 by forming another image thereon newly. At this time, that is to say, at the end of printing, the intermediate transfer roller 4 and the inking roller 3 are separated from the image recording body 10 and the cleaning unit 8 is brought into contact with the image recording body 10 so that the ink remaining thereon can be removed. After removal of the ink remaining on the image recording body 10, another liquid layer is formed on the surface of the image recording body 10 and the image recording body 10 is heated by means of the infrared heater 7 to treat the surface of the image recording body 10 so as to become the liquid-attracting state, while erasing the latent image of the previous image. However, in addition to the above method, as a method for treat the surface of the image recording body 10 so as to become the liquid-attracting state, it is possible to heat in a state where the liquid is come into contact with the surface of the image recording body 10 or for the surface of the image recording body 10 to bring into contact with the liquid right after heating the surface. In other words, as mentioned above, after printing a predetermined press run on the recording paper 5, the ink remaining on the image recording body 10 is removed and the latent image (a liquid-repelling region) formed on the image recording body 10 is erased, and the surface of the image recording body is then treated so as to become the liquid-attracting state. In this way, a new image (a latent image) can be formed on the image recording body 10 so that the image recording body 10 can be reused. That is to say, reuse of the image recording body 10 can be achieved by the following steps of: removing the ink remaining on the image recording body 10; forming the liquid layer on the surface of the image recording body by means of the liquid layer-forming roller 9; and heating the surface of the image recording body 10 by means of the infrared heater 7 to perform the liquid attracting treatment of the image recording body 10. As the cleaning unit 8, it is possible to use a waste 8b soaked with a cleaning liquid from the cleaning supply container 8a. The surface of the image recording body 10 is washed by pressing it with this waste 8b. 
In writing of the image into the image recording body, there are positive writing and negative writing. As negative writing, by heating the image recording body 10 in a state where the body 10 is come into contact with an element selected from the liquid and/or a solid, or brought into contact with the element selected from the liquid and/or the solid right after the surface of the image recording body 10 is heated, the receding contact angle of an image region of the image recording body decreases so as to subject the surface of the image recording body 10 to the liquid-attracting treatment. By selectively heating a non-image region of the image recording body in the absence of the above contacting element, the receding contact angle of the non-image region of the image recording body increases so as to subject the surface of the image recording body to the liquid-repelling treatment. On the other hand, as positive writing, by selectively heating only the image region of the image recording body 10 in a state where the body is come into contact with the element selected from the liquid and/or the solid, or selectively brought into contact with the element selected from the liquid and/or the solid right after selectively heating the surface of the body, the image region of the image recording body 10 is subjected to the liquid-attracting treatment.
As stated above, in the image forming apparatus according to the present invention, the liquid-attracting treatment is performed on the image recording body 10 according to image information. The ink is attached to portions of the image recording body 10 subjected to the liquid-attracting treatment and the ink attached to the body 10 can be directly transferred to the recording paper 5 through the intermediate transfer roller 4 so as to achieve transfer and printing steps.
As described above, the image recording body 10 can be reused by the following steps of: printing the predetermined press run onto the recording paper 5; erasing the latent image (the liquid-attracting region) formed on the body 10 and removing the ink remaining thereon; and forming a new image (the latent image) on the body 10. That is to say, reuse of the image recording body 10 can be carried out by removing the ink remaining on the body 10 by use of the cleaning unit 8 or other means and then heating the image recording body 10 by means of the infrared heater 7 to provide the liquid-attracting state for the surface of the image recording body 10.
Japanese Laid-Open Patent Application No. 3-178478 describes a recording method by use of a thermosensitive material having changeable character of wettability. Japanese Laid-Open Patent Application No. 8-276663 describes a recording method by negative writing. However, the invention of the above patent application No. 3-178478 mainly relates to the recording method by means of a thermal head in which there may be occasions that a recording layer is mechanically damaged due to contact recording between the thermal head and a recording body having the recording layer. Also, for the recording method by negative writing described in the above patent application No. 8-276663, an efficiency of light-heat conversion of a light source is not enough high because of continuous oscillation of the light source. There are problems that writing for the above method is time-consuming and is required to employ an expensive device as the light source.
Further, in the recording method disclosed in the above patent application No. 8-276663, there are disadvantages that a lifetime of the light source is shorter as compared to positive writing.
Moreover, in a case where the above recording body having a light-heat converting layer, for example in a case of writing by means of laser light, when incident light from a surface of the recording layer is reflected at a surface of a substrate through the recording layer and the light-heat converting layer, regular reflecting component is strong and this component reaches a boundary surface between the light-heat converting layer and the recording layer or the surface of the recording layer, thereby leading to multi-reflections within the above layers. This results in spreading of exposed areas and a recording irregularity, such as a moire.
In addition, in order to reuse the recording body used once, a clear printing can not be performed with a recording paper fouled by the remaining ink unless the ink remaining on the recording body is removed completely.
Furthermore, in a case of writing to the recording body by use of a plurality of heating means, if only one of the heating means is broken, a non-image region which is not heated is produced, thereby giving rise to a line of scumming.
In a case where negative writing is also carried out, an irregularity in heating and cumulative heat of an image forming means during negative writing operation cause the image to be degraded.
In a case where negative writing is also performed through a rotating multi-face mirror, if sensitivity of the recording body is low, a rotation rate of the rotating multi-face mirror must be low, so that the rotation rate is unstable because of the absence of an action of inertia induced by the rotation. This result in an irregularity of the light-heat conversion, thus producing irregularities relating to an image density, dot size and dot line.
A technical feature of the present invention resides in an image recording body comprising an element, which absorbs light (which includes an electromagnetic wave) in response to image information to achieve recording, provided in a recording layer of the image recording body formed on an uppermost layer thereof comprising a material having thermal changeable character of wettability, or in a substrate of said image recording body or an intermediate layer thereof, thereby improving a light-heat conversion efficiency in the light-stimulated writing.
The present invention provides the recording body having the highest efficiency of the light-heat conversion, in which the material having the thermal changeable character of wettability includes an organic material comprising an element having the changeable character of wettability and an element which absorbs the light (which includes the electromagnetic wave) in response to image information to achieve recording.
According to the above invention, by dissolving or dispersing a dye or a pigment which absorb light (which includes the electromagnetic wave) in the material which exhibits the thermal changeable character of wettability so as to contain the dye or the pigment in the above material, the recording body comprises a recording material and a absorbing material, so that there is a wider selection for the recording and the absorbing materials.
According to the above invention, by providing a reflecting layer which reflects light (which includes the electromagnetic wave) placed between the recording layer comprising the material having the changeable character of wettability and the substrate, a number of reflections takes place at the recording body so that a optical path length in the redording layer extends, thereby increasing the efficiency of the light-heat conversion.
According to the above invention, a rough surface of the reflecting layer results in a scattering of the light, so that an even penetration of the light can be carried out.
The present invention further provides a recording apparatus by use of the recording body comprising the material showing the changeable character of wettability which is sensitive of heat, in which scannable light can be used as an image writing source and a long lifetime of the writing source can be realized as a positive light-stimulated writing by providing a liquid layer forming means for forming a liquid layer on a surface irradiated by the light of the recording body during the light-stimulated writing.
According to the above invention, when the liquid layer forming means is means for forming a gel-like element, both of an easy holding of the liquid layer and a liquid supply can be realized simultaneously.
According to the above invention, when the liquid layer forming means is means for forming a layer comprising a microcapsule-like fine particle element containing a liquid, stability both for the liquid supply and the liquid storage can be ensured.
According to the above invention, by providing a light (which includes the electromagnetic wave) transmissible film for the liquid layer forming means in order to keep the liquid layer between the liquid forming means and the surface of the recording body so as to form the film on the surface of the recording body in a state where the liquid is placed between the liquid layer forming means and the recording body, a High speed writing can by obtained easily.
The recording body according to the present invention comprises a recording layer, a light-heat converting layer, a base body and a regular reflection-preventing layer between the base body and the light-heat converting layer to inhibit the regular reflection of light which is used for writing. This results in weakness of the regular reflection component in a case of reflection at a surface of the base body, so that multi-reflection can be lowered within each layer.
The recording body according to the present invention comprises the recording layer, the light-heat converting layer, the base body has a finely irregular structure provided on a surface of a light-heat converting layer side thereof in order to inhibit the regular reflection of light which is used for writing. This results in weakness of the regular reflection component of the light without an increase in the number of the layer, so that multi-reflection can be lowered within each layer.
The recording body according to the present invention comprises a recording layer having a light-heat converting agent dispersed therein, a regular reflection-preventing layer to inhibit the regular reflection of light which is used for writing and passes through the recording layer and a base body carrying the regular reflection-preventing layer. The regular reflection component is weakened in a case of reflection at a surface of the base body, thereby lessening multi-reflection within each layer.
The recording body according to the present invention comprises a recording layer having a light-heat converting agent dispersed therein and a base body carrying the recording layer. By providing an finely irregular structure on a surface of a recording layer side of the base body in order to inhibit the regular reflection of light which is used as writing and passes through the recording layer, the regular reflection component can be weakened in the event of reflection at the base body of the substrate without increase in the number of the layer, so that multi-reflection can be lowered within each layer.
Since the recording body according to the present invention comprises a recording layer, a light-heat converting layer, a transparent base body and a regular reflection-preventing layer to inhibit the regular reflection of light which is used to record onto an opposite side of the light-heat converting layer to the transparent base body, a regular reflection component can be weakened in a case of reflection at a back surface of the transparent base body, so that multi-reflection can be lowered within each layer.
The recording body according the present invention comprises a recording layer, a light-heat converting layer and a transparent base body. Since the transparent base body comprises a back surface thereof having a finely irregular structure, the surface being arranged in an opposite side to the light-converting layer having the finely irregular structure, the regular reflection component can be weakened in the event of the reflection at the back surface of the transparent base body without increase in the number of the layer.
Since the recording body according to the present invention comprises a recording layer having a light-heat converting agent dispersed therein, a transparent base body carrying the recording layer, a regular reflection-preventing layer provided on a surface arranged in an opposite side to the recording layer on the transparent base body in order to inhibit the regular reflection of light which is used for recording, the regular reflection component can be weakened in a case of reflection at a back surface of the transparent base body, so that multi-reflection can be lowered within each layer.
Since the recording body according to the present invention comprises a recording layer having a light-heat converting agent dispersed therein and a transparent base body, the transparent base body having a finely irregular structure on an opposite surface to the light-heat converting layer, the regular reflection component can be weakened in the event of reflection at the back surface of the transparent base body without increase in the number of the layer, so that multi-reflection can be lowered within each layer.
According to the present invention, in a carrier of the recording body carrying a transparent recording medium against light which is used for recording, by providing a reflecting layer on the surface of the carrier of the recording body in order to inhibit the regular reflection of the light which is used for recording, the regular reflection component can be weakened in the event of the reflection at the surface of the carrier, so that multi-reflection can be lowered within each layer.
According to the present invention, in a carrier of the recording body carrying a transparent recording medium against the light which is used for recording, by providing a finely irregular structure on the surface of the carrier, the regular reflection component can be weakened in a case of reflection at the surface of the carrier without increase in the number of the layer, so that multi-reflection can be lowered within each layer.
The recording body according to the present invention comprises a recording layer having the thermal changeable character of wettability and a substrate carrying the recording layer. The recording layer of the recording body is heated to form a latent image on the recording layer and the latent image is developed to transfer to a recording paper. The recording body has a surface having a roughness of less than 20 xcexcm.
The recording body according to the present invention comprises a recording layer having the thermal changeable character of wettability and a substrate carrying the recording layer. The recording layer of the recording body is heated to form the latent image on the recording layer and the latent image is then developed to transfer to the recording paper. The recording body has the recording layer having a pencil hardness of more than H.
The recording body according to the present invention comprises a recording layer having the thermal changeable character of wettability and a substrate carrying the recording layer. The recording layer of the recording body is heated to form the latent image on the recording layer and the latent image is developed to transfer to the recording paper. The recording body has the recording layer having a Young""s modulus of less than 1.0xc3x97107 N/m2 and a thickness of more than 2 xcexcm.
The recording body according to the present invention comprises a recording layer having the thermal changeable character of wettability and a substrate carrying the recording layer. The recording layer of the recording body is heated to form the latent image on the recording layer and the latent image is then developed to transfer to the recording paper. The recording body has the substrate having a Young""s modulus of less than 5.0xc3x97108 N/m2 and a thickness of more than 25 xcexcm.
The recording body according to the present invention comprises a recording layer having the thermal changeable character of wettability, a substrate and a cushion layer which is placed between the recording layer and the substrate and has a elastic property. The recording layer of the recording body is heated to form the latent image on the recording layer and the latent image is then developed to transfer to the recording paper. The recording body comprises the cushion layer having a Young""s modulus of less than 8.0xc3x97107 N/m2 and a thickness of more than 5 xcexcm.
According to the present invention, a method of removing an ink remaining on a recording body having the thermal changeable character of wettability, the method comprising the steps of coating a liquid which is compatible with a resin and a pigment which are contained in a recording ink on the recording body, and then wiping the liquid thus coated.
According to the present invention, a method of removing an ink remaining on a recording body having the thermal changeable character of wettability, the method comprising the steps of coating an involatilizable or a volatilizable solvent which is contained in a recording ink on the recording body, and then wiping the solvent thus coated.
According to the present invention, a method of removing an ink remaining on a recording body having the thermal changeable character of wettability, the method comprising the steps of coating a liquid which is compatible with a resin and a pigment which are contained in a recording ink on the recording body, and then supersonically cleaning the recording body.
According to the present invention, a method of removing an ink remaining on a recording body having the thermal changeable character of wettability, the method comprising the steps of coating a involatilizable or a volatilizable solvent which is contained in a recording ink on the recording body, and then supersonically cleaning the recording body.
According to the present invention, the surface of the recording body is cleaned after removal of the ink remaining on the recording body by any one of the methods described above.
According to the present invention, a method of removing an ink remaining on a surface of a recording body having the changeable character of wettability, the method comprising the steps of bringing a adhesive element into contact with the surface of the recording body developed already, and then stripping the adhesive element from the surface of the recording body, so that the remaining ink can be removed from the surface of the recording body together with the adhesive element.
According to the present invention, a method of removing an ink remaining on a surface of a recording body having the changeable character of wettability, the method comprising the steps of bringing an element having a rougher surface than that the surface of the recording body into contact with the surface of the recording body developed already, and then stripping the element from the surface of the recording body, so that the remaining ink can be removed from the surface of the recording body together with the element.
According to the present invention, a method of removing an ink remaining on a surface of a recording body having the changeable character of wettability, the method comprising the steps of forming a solid film on the surface of the recording body developed already, and then stripping the solid film from the surface of the recording body, so that the remaining ink can be removed from the surface of the recording body together with the solid film.
According to the present invention, a method of removing an ink remaining on a surface of a recording body having the changeable character of wettability, the method comprising the steps of completely curing the ink remaining on the surface of the recording body by an air drying, and then removing the ink by any one of the method described above.
According to the present invention, a method of removing an ink remaining on a surface of a recording body having the changeable character of wettability, the method comprising the steps of completely curing the ink remaining on the surface of the recording body compulsorily, and then removing the ink by any one of the method described above.
According to the present invention, an image forming apparatus comprising an image forming means for forming a latent image on an image region of a recording body by selectively heating a non-image region of a recording body, in which the latent image formed on the recording body is developed to transfer to a recording paper, wherein the image forming means comprises a plurality of heating sources for the recording body (that is to say, a multi-head), so that a same pixel can be heated by the plurality of heating sources and if a failed heating source is produced during writing, formation of a non-image region due to non-heating can be prevented, thereby eliminating generation of a line of scumming.
In the above invention, when a part of the multi-head is always heated to produce a failed heating source and the failed heating source is located at a marginal region, a region to be written by the failed heating source is not compensated by other heating source, so that time required for writing compensation is saved, thereby allowing capacity of control program to be reduced.
In the above invention, the image forming means comprises a multi-head having a broader recording width than that of an image formation area. A heating failure due to too much use can be inhibited by move the multi-head in a main scanning direction each time a predetermined printing is carried out.
In the above structure of the apparatus according to the present invention, the image forming means comprises a multi-head having a broader recording width than that of an image formation area. A heating failure due to too much use can be inhibited by move the multi-head in a main scanning direction every predetermined period.
In the above invention, the image forming means comprises heating means for heating an image region and heating means for heating a marginal region. A heating failure due to too much use can be inhibited by the above image forming means.
In the above invention, by using the heating means for heating the marginal region comprising the multi-head having a lower resolution than that of the heating means for heating the image region, so that a heating time for the marginal region can be shortened, thereby reducing a time for image formation.
In the above structure of the apparatus according to the present invention, a resistance value of each heating source of the multi-head and/or a voltage across a resistant element connected in series with the heating source are detected to examine whether or not the failed heating source is present by comparing the detected voltage with a defined voltage. If the failed heating source is generated, no formation of a non-image region by non-heating can be prevented, thereby eliminating generation of a line of scumming.
In the above structure, as a negative writing means, the image forming means heats the recording body in a state where the recording body is in contact with an element selected from a liquid and/or a solid, the recording body having surface properties in which a receding contact angle decreases (a liquid-attracting state) when the recording body comes into contact with the liquid in a heated state thereof and the receding contact angle increases (a liquid-repelling state) when the recording body is heated in a non-contact state with the liquid. Alternatively, right after a surface of the recording body is heated, the surface comes into contact with the element selected from the liquid and/or the solid to decrease the receding contact angle of the surface of the recording body, that is to say a liquid-attracting treatment. And then, an entire area of the surface of the recording body becomes liquid-attracting state and a region not to be recorded is then heated selectively by the image forming means in the absence of the liquid and/or the solid to make the region liquid-repelling state.
In the above structure, the image forming means comprises a plurality of heating sources corresponding to a respective recording ink color, so that a multi-color image can be obtained with high quality.
According to the present invention, an image forming apparatus comprising an image forming means for forming a latent image on an image region of a recording body by selectively heating a non-image region of the recording body, wherein the image forming means has a function that a writing heat quantity can be adjusted and a heated temperature can be adjusted to prevent an irregularity of heating.
In the above structure, the image forming means has a function that the writing heat quantity can be adjusted in response to temperature information of the recording body, so that an optimal heat quantity can be supplied based on a standard temperature of the recording body, thereby allowing a high quality image to be produced.
In the above invention, the image forming means has a function that the writing heat quantity can be adjusted in response to heating information of a pixel neighboring a pixel to be heated (a pixel of interest) and the pixel written with the pixel of interest at the same time or the pixel written already, so that the influence of a temperature irregularity on the pixel of interest in accordance with a heated state of the neighboring pixel can be inhibited and formation of a high quality image can be carried out.
In the above structure, by using the image forming means, for the pixel of interest the writing heat quantity can be changed in accordance with a heat record of a plurality of written lines which are in the same scanning direction or are in a near position and the influence of the temperature irregularity on the pixel of interest in response to the heat record of the written plurality of lines, thereby producing the high quality image.
In the above structure, the image forming means comprises the multi-head having a plurality of the heating source for the recording body. By changing the heat quantity form the multi-head in accordance with the number of the heating sources driving simultaneously, an irregularity of the heat quantity produced by the heat quantity of the heating source driving simultaneously can be inhibited, thereby producing the high quality image.
In the above structure, by using the image forming means, writing can be carried out every at least other line in a sub-scanning direction, so that accumulation of heat can be prevented during writing, thus allowing the high quality image to be produced while suppressing the thermal irregularity.
In the above structure, a writing rate can be changed in response to image information by use of the image forming means, so that an irregularity of accumulation of heat can be prevented during various writing in accordance with image information, thereby allowing the high quality image to be produced.
In the above structure, the writing rate can be changed in response to an increased temperature of the recording body by use of the image forming means, so that an increase in the temperature of the recording body can be lowered during writing, thereby producing the high quality image.
In the above structure, image formation can be carried out by increasing the heat quantity at an initial writing by use of the image forming means, so that a deficiency in the heat quantity can be prevented before the temperature of the recording body is stabilized, thereby producing the high quality image.
In the above structure, the image forming means comprises the multi-head and the pixel in the same line can be recorded more than every at least other pixel, so that accumulation of heat can be inhibited and the irregularity of heating can be eliminated to produce the high quality image.
In the above structure, the image forming means comprises the multi-head having a plurality of heating sources, each heating source being formed more than every other pixel, so that accumulation of heat can be inhibited and the irregularity of heating can also be eliminated to produce the high quality image.
In the above structure, the image forming means comprises the multi-head and the-pixel in the same line and in a spiral line can be recorded every at least other pixel, so that accumulation of heat can be inhibited and the irregularity of heating can also be eliminated to produce the high quality image.
In the above structure, the image forming means comprises the multi-head and the pixel in the same line can be recorded every at least other pixel. After the last line is completed, the image forming means or the recording body is movable in the main scanning direction to continue formation of the image, so that accumulation of heat can be inhibited and the irregularity of heating can also be eliminated to produce the high quality image.
In the above structure, as a negative writing means, the image forming means heats the recording body in a state where the recording body is in contact with an element selected from a liquid and/or a solid, the recording body having surface properties in which a receding contact angle decreases (a liquid-attracting state) when the recording body comes into contact with the liquid in a heated state thereof and the receding contact angle increases (a liquid-repelling state) when the recording body is heated in a non-contact state with the liquid. Alternatively, right after a surface of the recording body is heated, the surface comes into contact with the element selected from the liquid and/or the solid to decrease the receding contact angle of the surface of the recording body, that is to say a liquid-attracting treatment, thereby making an entire area of the surface of the recording body liquid-attracting state and then a non-image region of the recording body is heated selectively by the image forming means in the absence of the contacting element, such as the liquid and/or the solid to make a region not to be recorded the region liquid-repelling state.
In the above structure, the image forming apparatus comprises a plurality of image forming means corresponding to a respective recording ink color, so that a multi-color image can be obtained with high quality.
According to the present invention, an image forming apparatus comprising a laser source controlled to emit laser light in response to image information, a rotating multi-face mirror to scan the laser light from the laser source, a motor to rotate the rotating multi-face mirror, and a recording body irradiated with the laser light reflected by the rotating multi-face mirror, in which a latent image is formed on the recording body by irradiating the laser light in response to image information, wherein the recording body is a low sensitive recording body comprising a light-heat converting material which converts the laser light irradiated onto the recording body to heat, the rotating multi-face mirror is stably rotated at a low rate with a rate reducing means to which the motor is rotated at a high rotation of a stable rotation region to transmit a rotating force, so that a rotation of the multi-face mirror can be stabilized to allow a scanning rate and a scanning time of the laser light to be constant and lesser irregularities of an image density, dot and a line size (for example, broadening or narrowing) can be obtained to provide an inexpensive light scanning apparatus.
In the above invention, by providing a disk-like mass member having a weight equal to or more than that of the rotating multi-face mirror for the motor or a rotating axis of the rotating multi-face mirror, the rotation of the multi-face mirror can be stabilized at the low rate, so that lesser irregularities of an image density, dot and a line size (for example, broadening or narrowing) can be obtained to provide an inexpensive light scanning apparatus.